Mechanism for mitigating filler-induced reliability degradation in semiconductor devices assembled utilizing an LOC package technique

This work illustrates a mechanism for mitigating filler-induced reliability degradation in semiconductor devices assembled utilizing an LOC (lead-on-chip) package technique. Based on the mechanism, this article provides two fundamental solutions to solve the filler-driven problem in semiconductor products. First of all, in order to avoid filler-driven pattern damage during thermal-cycling, the maximum filler size in the plastic package body should have a diameter smaller than half of the inter-distance between the device pattern and it’s overlying lead-frame. Second, for effective prevention of filler-induced failure, the minimum distance between the polyimide coverage and each pad should be maintained to have a dimension that corresponds to the polyimide thickness. This article conclusively shows that the proper combination of two solutions can allow semiconductor products to have better reliability margins in use.